[3.11.y.z extended stable] Patch "tty: serial: 8250_core.c Bug fix for Exar chips." has been added to staging queue

Luis Henriques luis.henriques at canonical.com
Wed May 14 14:57:32 UTC 2014

This is a note to let you know that I have just added a patch titled

    tty: serial: 8250_core.c Bug fix for Exar chips.

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:


If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see



>From 61b9e9fc77bc5bbcf41c974992f6dff9019f150a Mon Sep 17 00:00:00 2001
From: Michael Welling <mwelling at ieee.org>
Date: Fri, 25 Apr 2014 19:27:48 -0500
Subject: tty: serial: 8250_core.c Bug fix for Exar chips.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit b790f210fe8423eff881b2a8a93ba5dbc45534d0 upstream.

The sleep function was updated to put the serial port to sleep only when necessary.
This appears to resolve the errant behavior of the driver as described in
Kernel Bug 61961 – "My Exar Corp. XR17C/D152 Dual PCI UART modem does not
work with 3.8.0".

Signed-off-by: Michael Welling <mwelling at ieee.org>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
 drivers/tty/serial/8250/8250_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 9d5c661..d8c06a3 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -555,7 +555,7 @@ static void serial8250_set_sleep(struct uart_8250_port *p, int sleep)
 	if ((p->port.type == PORT_XR17V35X) ||
 	   (p->port.type == PORT_XR17D15X)) {
-		serial_out(p, UART_EXAR_SLEEP, 0xff);
+		serial_out(p, UART_EXAR_SLEEP, sleep ? 0xff : 0);


More information about the kernel-team mailing list